Tips & Tricks for Optimizing Your Emails

Email Marketing


I’ll admit it. Email marketing is scary. You pour your heart and soul into an email–crafting creative copy, compelling imagery, and the perfect subject line just to hit send and get judged by thousands of subscribers (or at least it feels that way sometimes).

Unfortunately, the reality is that not every email you send will be a winner. Luckily, with sound testing methodology and an exhaustive list of A/B testing ideas, you can learn how to better engage subscribers and send your email performance through the roof!

Email Elements to Test

Looking at which email elements to test can be a bit daunting. After all, there are plenty of ways to slice the pie (as a pie aficionado, I would know).

Here are 25 elements you can consider testing in your emails:

  1. Subject line
  2. From name
  3. Day of week sent
  4. Time of day sent
  5. Cadence
  6. Links vs. buttons
  7. Image-based CTAs vs. HTML CTAs (aka bulletproof buttons)
  8. HTML vs. text
  9. Subject line character length
  10. Social sharing icons
  11. Preheader text (text preview following the subject line)
  12. Personalization–first name, company name, address, etc.
  13. Header height
  14. One column vs. two columns vs. three columns
  15. Video in email
  16. Using lists and numbers
  17. P.S. note in email footer
  18. Using trust icons
  19. CTA placement
  20. Short copy vs. long copy
  21. Social proof
  22. Mobile optimization
  23. Special characters in subject line
  24. Declutter
  25. Resending to non-openers

Alright, so maybe this list is a little overwhelming, but at least it’s exhaustive!

Since one of the most common email marketing tests is subject line testing, let’s take a moment to talk about what makes for a good subject line:

  • Front-load the important words. People want to know why your email is worth their time, so put all the important, actionable words in the front of your subject line to entice opens. In other words, get to the point! In my experience, changing the structure of the sentence line to front-load the important keywords has increased open rates by 10-20%.
  • Get personal. There’s usually at least one person in every office who can’t seem to remember anyone’s first name. For the record, no one likes that, especially not your email subscribers. Address your subscribers by their name or, at the very least, insert pronouns like “you” or “your” to give your subject lines a personalized touch.
  • Use rhymes, alliteration, and puns. If you can write a subject line that rolls off the tongue, you will get a higher open rate. It’s like music to the ears! It’s not easy to come up with these but when you do, they will perform exceedingly well. In fact, I’ve seen extraordinary subject line performance where I’ve beaten the control by 30-40%!
  • Write clearly. Let’s just come out and say it. When it comes to emails, we have short attention spans. We don’t have time to sit there and read everything carefully. We need to know what’s important and that’s it. Use clear and concise language when writing subject lines. The last thing you want is to write a subject line that requires a double take just to understand it.

Take these subject line writing tips out for a spin in your next email test! Remember that first impressions matter. The subject line is like a handshake hello. If you get it right, your subscribers will love you from the start.

5 Best Practices for Email Testing

Done right, A/B testing increases engagement, enhances campaign effectiveness, and informs marketers about audience preferences. For good measure, let’s go over testing best practices.

Here are five pro tips for email testing:

  1. Keep it simple. Test basic elements first: subject lines, “from” names, and email copy. It doesn’t take too much time or creative work to come up with a few simple tests.
  2. Standardize email send times. When running any A/B test, be sure to normalize your send times. Even a 30-minute difference can drastically change the results of your test. Do your best to send emails together at the optimal send time for your subscribers.
  3. Choose your sample sizes wisely. If your sample size is too small, you may be calling a winner without actually having one. As a good rule of thumb, make sure that you have at least 1,000 observations for any test. For instance, if you’re running a subject line test, you need at least 1,000 opens per email to see statistical significance. If you can’t find significance, you should run the test again and aggregate the data.
  4. Test one element at a time. It’s tempting to want to test more than one variable at a time because you’d assume the more you test at once, the bigger the impact you can make and the faster you can make improvements. But the challenge is that you wouldn’t know the individual improvements or decline in each variable. Test one variable at a time, measure the results, and roll out the winners into your new emails over time.
  5. Listen to your test results. You’ll see testing results that make no sense. You won’t want to believe your eyes. But email marketing isn’t a cupcake competition. The best, most engaging email might not be the prettiest, or your favorite. Trust the data and your email results will be stellar!

Email Metrics to Track

As the saying goes, you can’t manage what you can’t measure. No email test is complete without the right metrics to measure them.

Let’s cover some important email marketing metrics:

  • Total number of emails sent
  • Total number of emails delivered
  • Deliverability rate: Delivered emails/sent emails (expressed as a percentage)
  • Unique number of emails opened
  • Open rate: Opened emails/delivered emails (expressed as a percentage)
    • Use this metric when you’re evaluating your subject line tests.
  • Unique number of email clicks
  • Click-to-open rate: Unique clicks/unique opened emails (expressed as a percentage)
    • When you’re running an A/B test involving unique elements within the email such as copy, call-to-action, or imagery, the click-to-open rate is your metric of choice. Since your subject lines stay the same (just test one variable at a time), the click-to-open rate will tell you how the email performed AFTER it was opened by the recipient.
  • Click-through rate: Unique clicks/emails delivered (expressed as a percentage)
    • A/B tests for subject lines can use the click-through rate metric. Subject lines affect both open rates and click-to-open rates. The click-through rate metric will give you an all-inclusive metric to measure your subject line tests. Remember that a subject line that beats the control on open rate but loses on click-to-open rate is not necessarily the winner. Look for subject lines that outperform the control across all metrics.
  • Unique number of unsubscribes
  • Unsubscribe rate: Unique unsubscribes/emails delivered (expressed as a percentage)

I hope this blog has helped give you some testing ideas as well as a foundation for how to test. Do you have a favorite test that I didn’t mention here? Share it below!

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